Glossary

Lines or markings that extend outward from the center of a fastener’s head toward its outer edge. In bolts and screws, these radial lines serve as grade markings to indicate strength classification. For example, SAE J429 fasteners use three radial lines to signify Grade 5 and six radial lines for Grade 8.

The reddish-brown corrosion that occurs when the steel base of any fastener, plated or coated, is exposed to moisture and begins to oxidize. Red rust damages the structural integrity and ductility of the fastener. Once red rust appears, fasteners should be replaced to maintain assembly strength and prevent equipment damage.

An industrial regular square nut is a type of fastener commonly used in mechanical and industrial applications. It has a square shape with four equal sides and a threaded hole in the center, designed to mate with a bolt or threaded rod. The square design provides several advantages over hexagonal nuts, such as greater surface area for contact with the material being fastened, which can improve resistance to loosening under vibration or torque. It also allows for easy tightening with a wrench, as the flat sides offer a good grip.

You may be familiar with them being called Serrated Shoulder Bolts or Ribbed Bolts. However you refer to them, they often secure the bed of a truck to its frame. The Ribbed Neck Carriage Bolts are perfect for assembling wood, plastic, or soft metals requiring high wear resistance applications. The low-profile head ensures that there is no interference with objects as they slide over the head. The ribbed neck prevents the bolts from loosening over time. Earnest carries Ribbed Neck Carriage Bolts in Grade 5.

Threads that tighten when turned clockwise (to the right). This is the most common thread direction used in fasteners, meaning the fastener is screwed in by turning it to the right and loosened by turning it to the left.

A ring eye bolt is a type of lifting or anchoring fastener that features a round, closed loop (ring) at one end and a threaded shank at the other. It is used to attach ropes, cables, or chains and can serve as a lifting point, tie-down, or suspension anchor.

A rivet nut, also known as a rivnut or blind nut, is a tubular, internally threaded fastener used to add strong, reusable threads to thin or soft materials like sheet metal and plastics. It is installed into a pre-drilled hole and then deformed on the blind side using a special setting tool, which locks it securely in place without needing access to both sides of the material.

Rivet nuts are commonly used in automotive, aerospace, electronics, and furniture applications, where they provide a durable fastening point in materials that cannot be tapped for conventional threads. They are especially useful in blind applications and offer a vibration-resistant, permanent solution for mounting bolts or screws.

A rock bolt is a long, heavy-duty anchor used to stabilize rock formations in tunnels, mines, slopes, or other excavations. It is drilled into rock and either mechanically or chemically anchored to hold together loose or potentially unstable rock layers.

A rod is a long, solid cylindrical metal or composite bar used in various manufacturing, construction, machining, and engineering applications. Industrial rods are designed to provide structural support, reinforcement, or mechanical functionality in heavy-duty environments.

A roll pin, also called a spring pin, is a hollow, cylindrical fastener made of spring steel with a small gap along its length. When pressed into a slightly undersized hole, it compresses and exerts outward tension, which securely locks it in place without the need for threads or additional hardware. This self-retaining design makes it simple yet highly effective for joining or aligning parts.

Roll pins are commonly used in machinery, tools, and automotive applications where vibration resistance and durability are important. They come in slotted or coiled varieties, with coiled versions offering greater strength and fatigue resistance. Because of their resilience and reusability, they’re widely relied upon for dynamic assemblies.

Rolled threads are created by deforming the fastener’s surface through a rolling process using hardened dies, which displace and compress the fastener to form the thread profile without removing any material. This process creates stronger threads with a smoother surface finish compared to cut threads.

A roller eye bolt is a specialized type of eye bolt that includes a built-in roller or pulley mechanism within the eye loop. It’s designed for guiding, redirecting, or supporting cables, ropes, or wire while minimizing friction and wear.

Roofing nails are specialized nails used to attach roofing materials—like shingles, felt paper, sheet metal, or roofing tiles—to wooden or other structural substrates. They are specifically designed for durability, weather resistance, and holding power in demanding outdoor conditions.

A rosette weld nut is a weldable fastener that features small holes or slots—shaped like a rosette—in its base. These openings allow molten metal to flow through during welding, fusing the nut more securely to the parent material than a flat weld nut would. The result is a strong, permanent threaded connection that resists torque and pull-out.

They are commonly used in automotive, aerospace, and machinery applications where threaded holes need to be added to thin sheet metal or structural components. By providing additional weld points through the rosette holes, this nut design ensures greater strength and durability compared to standard weld nuts.

A destructive, reddish-brown corrosion that forms on iron or steel fasteners due to exposure to oxygen and moisture weakening their structure and impeding function. It is commonly mitigated by the use of protective finishes or corrosion-resistant materials, like stainless steel.